Since the development of the surface treatment industry, the UV surface printing technology has been used in shell materials of cell phone by more and more companies. For example, the shell materials of cell phone of Nokia, Motorola and Sony-Ericsson and etc use the UV surface printing technology for printing LOGO or patterns. In the existing technology, the method is to print a UV-curable transparent clear paint over the oxidative polymerization drying oleiferous ink and use the UV light irradiation for drying. The method has the oleiferous ink's excellent printability and ease operation and time saving by UV curing. However, the oil ink needs long time to solidify so the luster of the printed matter by this method will be degraded. Furthermore, parts of the heavy metals and the solvent of oil needed by this oxidative polymerization drying oleiferous ink will residue in the printed matter and pollute the environment. In addition, if the drying is not sufficient, the wear resistance of the ink is bad and the printed LOGO on the surface of the plastic shell will be worn off. This will seriously damage the image of the shell shape.